Diversity of Fish Fauna and Water Quality in the Downstream of Batang Ai HEP, Engkilili, Sarawak

Jennifer Yong Phei Ling

Bachelor of Science with Honoun (Aquatic Resource Science and Management)

2016

P. KHIDI1AT I1AKLUI1AT AKADEI1IKPusa' I VNIVI

IIIIIIIIIIIIIIIIII~ 11111 1000272629

Diversity of Fish Fauna and Water Quality in the Downstream of Batang Ai HEP, Engkilili, Sarawak

Jennifer Yong Phei Ling

41544

This dissertation is submitted in partial fulfillment of requirement for the degree of Bachelor of Science with Honours in Aquatic Resource Science and Management

Aquatic Resource Science and Management Department of Aquatic Science

Faculty of Resource Science and Technology Universiti Malaysia Sarawak

2016

Acknowledgement

During the process of completion of my final year project, lots of people have made

their contribution and support to make it a success. First of all, I would like to express my

gratitude to my dearest supervisor, Prof. Dr. Lee Nyanti for his endless guidance, advices

and support throughout the whole journey of final year project.

I would also like to thank all the helpful laboratory assistants from Department of

Aquatic Science, Faculty of Resource Science and Technology especially to Mr. Richard

Toh, Mr. Benedict Samling, Mr. Mohd Nor Azlan, Mr. Mustafa Kamal and Madam Lucy

Daru during the field works and at the laboratory.

Besides, I would like to thank the boatman, Mr. Drafar who help me during my

field work and provide great hospitality at Engkilili. Not only that, I am thankful to

postgraduate students who provide guidance especially to Ms. Angie Sapis.

The financial support provided by Sarawak Energy Berhad through research grant

no. GL(F07)/SEB/5A/2013 (28) is also gratefully acknowledged.

A great thank you I would like to give to all my family members especially parents

for their continuous support during my hard time. Thank you too, to my close friends since

secondary school, especially to Bong Sze Ting, Sii Kia Teng, Chen Em Tze and Shirley

Chee for their moral support when I face obstacles even though they are not by my side.

Besides, I also would like to thank my close friend, course mate, field work mate and lab

mate, Karen Kho for her support and guidance. Last but not least, I would like to thank my

close friends in university, Suet Yee, Asang and Khai Han for their support throughout my

whole journey in UNIMAS, and to all final year students of Aquatic Science Department,

FRST for their cooperation.

I

Declaration

I, Jennifer Yong Phei Ling declare that the final year project report entitled:

Diversity ofFish Fauna and Water Quality in the Downstream of Batang

Ai HEP, Engkilili, Sarawak

and the work presented in the report are both my own, and have been generated by me as

the result ofmy own original research. I confirm that:

• this work was done wholly or mainly while in candidature for a research degree at

this University;

• where I have made corrections based on suggestion by supervisor and examiners,

this has been clearly stated;

• where I have consulted the published work of others, this lS always clearly

attributed;

• where I have quoted from the work of others, the source is always given. With the

exception of such quotations, this report is entirely my own work;

• I have acknowledged all main sources of help;

• where the thesis is based on work done by myself jointly with others, I have made

clear exactly what was done by others and what I have contributed myself;

• none of this work has been published before submission

Signed: W Aquatic Resource Science and Management Department of Aquatic Science Faculty of Resource Science and Technology Universiti Malaysia Sarawak (UNIMAS)

Date: 1t+h JUYl~ :20 lb II

,... P US!l j. n . '

• " a Akad 'm :' VNlVERSm MALAYSIA SARAWAJ\

Table of Contents Page

Acknowledgement I

Declaration II

Table of Contents III

List of Abbreviations VI

List of Tables VII

List of Figures IX

List of Equations XI

Abstract!Abstrak XII

1.0 Introduction 1

2.0 Literature Review 3

2.1 Diversity and Distribution of Freshwater Fishes 3

2.2 Dominant Species in Malaysia and Borneo 3

2.3 River System 4

2.4 Effects of Impoundment of Dam to Downstream Area 5

2.5 Feeding Habits 6

2.6 Length-Weight Relationship and Condition Factor 7

2.7 Water Quality 8

2.8 Oonadosomatic Index (OSI) and Hepatosomatic Index (HSI) 9

2.9 Threats to River 9

3.0 Materials and Methods 11

3.1 Study Site 11

3.2 Water Quality 13

3.2.1 Water Quality Parameters Measured In-situ 13

III

!

3.2.2 Water Quality Parameters Measured Ex-situ 13

3.2.2.1 Total Suspended Solids (TSS) 13

3.2.2.2 Biological Oxygen Demand in 5 Days (BODs) 14

3.2.2.3 Chlorophyll-a (ChI-a) 15

3.3 River Profile 16

3.4 Fish Sampling 17

3.5 Fish Identification 18

3.6 Fish Preservation 18

3.7 Fish Measurement 18

3.7.1 Oonadosomatic Index (OS I) 18

3.7.2 Hepatosomatic Index (HSI) 19

3.7.3 Feeding Habits 19

3.7.4 Length-Weight Relationship 20

3.8 Indices 21

3.9 Statistical Analysis 22

4.0 Results 23

4.1 Water Quality Parameters 23

4.1.1 Temperature 23

4.1.2 Conductivity 24

4.1.3 pH 25

4.1.4 Turbidity 26

4.1.5 Dissolved Oxygen 27

4.1.6 Transparency 28

4.1.7 Biological Oxygen Demand in 5 Days (BODs) 29

IV

,.. ... I

4.1.8 Chlorophyll-a 31

4.1.9 Total Suspended Solids (TSS) 31

4.2 River Profile 33

4.3 Fish Fauna 34

4.3.1 Fish Caught in August 2015 34

4.3.2 Fish Caught in February 2016 35

4.3.3 Fish Composition in August 2015 and February 2016 (Pooled) 37

4.4 Oonadosomatic Index (OSI) 39

4.5 Hepatosomatic Index (HSI) 40

4.6 Stomach Content Analysis 41

4.6.1 Frequency Occurrence 41

4.6.2 Mass Method 43

4.7 Length-Weight Relationship 45

4.8 Diversity, Richness and Evenness Indices 49

4.9 Principal Component Analysis 50

5.0 Discussion 52

6.0 Summary and Conclusion 60

7.0 References 62

Appendices 69

v

List of Abbreviations

L Litre

mL Millilitre

~g Microgram

TSS Total Suspended Solids

DO Dissolved Oxygen

BOD Biochemical Oxygen Demand

Chl-a Chlorophyll-a

E Absorption in Respective Wavelength

TL Total Length

SL Standard Length

BW Body Weight

GW Gonad Weight

SW Stomach Weight

GSI Gonadosomatic Index

HSI Hepatosomatic Index

°C Degree Celcius

mglL Milligram per Litre

H' Shannon-Wiener's Diversity Index

D Margalef s Species Richness Index

J' Pielou's Evenness Index

rpm Rotations per minute

LWR Length-weight relationship

VI

List of Tables

Table Description Page

Table 1 Coordinates of sampling stations in the downstream of Batang Ai 11

HEP, Engkilili, Sarawak.

Table 2 Fishing method(s) used for each station at downstream of Batang Ai 17

HEP, Engkilili, Sarawak.

Table 3 Stations, width of river, cross section area, water current and 33

discharge rate in the downstream of Batang Ai HEP.

Table 4 List of fish family and species, number of individuals caught (N) and 35

percentage (%) in the downstream of Batang Ai HEP during August

2015.

Table 5 List of fish family and species, number of individuals caught (N) and 37

percentage (%) in the downstream of Batang Ai HEP in February

2016.

Table 6 List of fish family and species, number of individuals caught (N) and 39

percentage (%) in the downstream of Batang Ai HEP during August

2015 and February 2016 (Pooled).

Table 7 Species, sex, number of individuals with gonads present, percentage 40

and average GSI values.

Table 8 Species, number of individuals and average HSI values. 41

Table 9 Frequency occurrence of different food items found in the stomachs 42

of six species.

Table 10 Total mass of each food item (TM) (g) and mass method of different 44

food items found in the stomachs of six fish species.

VII

List of Tables

Table

Table II

Table 12

Table 13

Description Page

Length-weight relationship for six dominant fish species from two 49

trips (August 2015 and February 2016).

Species diversity, species richness and species evenness in August 50

2015 and February 2016.

Principal component loadings of the 12 fish species on the first, 50

second and third axis.

VIII

List of Figures

Figure Description Page

Figure 1 Sampling stations in the downstream of Batang Ai REP, Engkili1i, 12

Sarawak (Source: Goog1e Map and Goog1e Earth).

(Bartram and Ballance, 1996).

February 2016 in the downstream of Batang Ai REP.

REP in August 2015 and February 2016.

August 2015 and February 2016.

in August 2015 and February 2016.

Ai REP in August 2015 and February 2016.

REP in August 2015 and February 2016.

August 2015 and February 2016.

REP in August 2015 and February 2016.

August 2015 and February 2016.

Figure 2 Cross section of a river divided for measurement of river discharge 17

Figure 3 Mean temperature values for each station In August 2015 and 23

Figure 4 Mean conductivity values recorded in the downstream of Batang Ai 24

Figure 5 Mean pH levels recorded in the downstream of Batang Ai REP in 26

Figure 6 Mean turbidity values recorded in the downstream of Batang Ai REP 27

Figure 7 Mean dissolved oxygen values recorded in the downstream of Batang 28

Figure 8 Mean transparency values recorded in the downstream of Batang Ai 29

Figure 9 Mean BODs values recorded in the downstream of Batang Ai REP in 30

Figure 10 Mean ch1orophyll-a values recorded in the downstream of Batang Ai 31

Figure 11 Mean TSS values recorded in the downstream of Batang Ai REP in 32

IX

List of Figures

Figure Description Page

Figure 12 Fish family composition in the downstream of Batang Ai HEP in 34

August 2015.

Ai HEP in February 2016.

Ai HEP in August 2015 and February 2016 (Pooled).

HEP.

Ai HEP.

HEP.

HEP.

HEP.

and fish species (blue lines).

Figure 13 Percentage of each fish family caught in the downstream of Batang 36

Figure 14 Percentage of each fish family caught in the downstream of Batang 38

Figure 15 LWR for Hampala macrolepidota in the downstream of Batang Ai 46

Figure 16 LWR for Barbonymus schwanenfeldii in the downstream of Batang 47

Figure 17 LWR for Kryptopterus parvanalis in the downstream of Batang Ai 47

Figure 18 LWR for Toxotes microlepis in the downstream of Batang Ai HEP. 48

Figure 19 LWR for Hemibagrus planiceps in the downstream of Batang Ai 48

Figure 20 LWR for Cyclocheilichthys apogon in the downstream of Batang Ai 49

Figure 21 peA ordination bi-plot of 9 physicochemical parameters (red font) 51

x

1

2

3

4

5

6

7

8

9

10

11

12

13

List of Equations

Equation Description Page

Equation Equation for total suspended solids. 14

Equation Equation for biological oxygen demand in 5 days (BODs). 14

Equation Equation for chlorophyll-a. 16

Equation Equation for discharge rate. 16

Equation Equation for gonadosomatic index (GSI). 19

Equation Equation for hepatosomatic index (HSI). 19

Equation Equation for frequency occurrence (Fj). 19

Equation Equation for mass method (Mjj). 20

Equation Equation for length-weight relationship (L WR). 20

Equation Equation for Fulton's condition factors (K). 21

Equation Equation for Shannon-Wiener's Diversity Index. 21

Equation Equation for Margalefs Species Richness Index. 21

Equation Equation for Pielou's Evenness Index. 21

XI

Diversity of Fish Fauna and Water Quality in the Downstream of Batang Ai HEP, EngkiJili, Sarawak

Jennifer Yong Phei Ling

Aquatic Resource Science and Management Faculty of Resource Science and Technology

Universiti Malaysia Sarawak

ABSTRACT

This research was conducted to document the diversity of fish fauna and fish composition along with selected water quality parameters in the downstream of Batang Ai HEP, Engkilili, Sarawak due to lack of infonnation on fish fauna in the downstream area of the hydroelectric power plant. Ten stations were selected for fish sampling and four stations for water quality parameters. Fishes were sampled using monofilament gill nets of different mesh sizes and three-layered nets. A total of 67 individuals were caught from all stations with Cyprinidae as the dominant family (40.30 %), followed by the families Siluridae (19.40 %), Bagridae (11.94 %), Toxotidae (8.96 %), Ariidae (4.48 %), Sciaenidae (2.99 %), Osphronemidae (2.99 %), Syngnathidae (1.49 %), Mugilidae (1.49 %), Datnioidae (1.49 %), Polynemidae (1.49 %), Carangidae (1.49 %) and Megalopidae (1.49 %). The six dominant species recorded were Kryptoptenls parvanalis with 13 individuals, followed by Hampala macrolepidota (10 individuals), Barbonymlls schwanenfeldii (9 individuals), Hemibagms planiceps (8 individuals), Toxotes microlepis (6 individuals) and Cyclocheilichthys apogon (6 individuals). Species diversity, species richness and species evenness values were higher during dry season which were 2.2990, 3.6831 and 0.6213, respectively as compared to wet season with species diversity, species richness and evenness of 2.1752, 2.9621 and 0.6068, respectively. Water quality results showed that temperature ranged from 27.66 °C to 28.82 °C, conductivity ranged from 23.09 JlS/cm to 24.63 JlS/cm, pH ranged from 6.71 to 7.03, turbidity ranged from 0.84 NTU to 7.95 NTU, dissolved oxygen ranged from 5.20 mglL to 7.20 mg/L, transparency ranged from 0.80 m to 1.35 m, BODs ranged from 4.67 mglL to 9.80 mglL, chlorophyll-a ranged from 0.00102 mg/L to 0.01863 mglL, and total suspended solids ranged from 4.87 mglL to 29.00 mgIL. The population of fish in the downstream of Batang Ai Hydroelectric

Power Plant showed relatively low number of individuals caught. Therefore, the fish assemblage in the downstream was impacted by the impoundment of hydroelectric power plant.

Keywords: Diversity, Fish fauna, Batang Ai, Downstream, Water quality

ABSTRAK

Kajian ini dijalankan IIntllk mendokumentasikan kepelbagaian fauna ikan dan komposisi ikan bersama dengan parameter kualiti air terpilih di hilir Batang Ai HEP, Engki/i/i, Sarawak kerana kekllrangan maklumat mengenai fauna ilean di kawasan hilir loji kuasa hidroelektrik. Sepuluh stesen telah dipilih ullluk pensampelan ikan dan empat stesen IIntllk parameler kualiti air. Ikon dilangkap menggunakan pukat yang memplmyai ukuran mata jaring yang berbeza dan pUkal tiga lapis. Seramai 67 individu telah ditangkap dari semua stesen dengan Cyprinidae sebagai keillarga yang dominan (40.30 %), diikuti oleh keluarga Siluridae (19.40 %), Bagridae (I /. 94 %). Toxotidae (8.96 %), Ariidae (4.48 %). Sciaenidae (2.99 %), Osphronemidae (2.99 %), Syngnathidae (/,49 %), Mugilidae (1.49 %), Datnioides (1.49 %), Polynemidae (/,49 %), Carangidae (1.49 %) dan Megalopidae (1.49 %). Enam spesies dominan direkodkan adalah Kryptopterus parvanalis dengan 13 individll, diikuti oleh Hampala macrolepidota (10 individll), Barbonymus schwanenfeldii (9 individu), Hemibagms planieeps (8 individu), Toxotes microlepis (6 individu) dan Cycloeheiliehlhys apogon (6 individu). Kepelbagaian spesies, kekayaan spesis dan spesies keseragaman adalah lebih tinggi semasa musim kering iaitu 2,2990, 3,6831 dan 0,62 I 3, masing-masing berbanding dengan musim basah yang mempunyai kepelbagaian spesies, kekayaan spesis dan keseragaman spesies 2,1752, 2,9621 dan 0.6068, masing-masing. Hasil analisi kllalili air menunjukkan bahawa suhu adalah antara 27.66 °C hingga 28.82 °C, kekonduksian anlara 23.09 IlSlcm hingga 24.63 IlSlcm, pH antara 6,71 hingga 7,03, kekemhan antara 0.84 NTU hingga 7.95 NTU, oksigen terlamt anlara 5.20 mg/L hingga 7.20 mg/L. kelelusan antara 0.80 m hingga /.35 m, BODj anlara 4.67 mg/L hingga 9.80 mg/L, klorojil-a antara 0,00102 mg/L hingga 0,01863 mg/L, danjumlah pepejallerampai antara 4.87 mg/L hingga 29.00 mg/L. Populasi ikan di hilir Loji Kuasa Hidroelektrik Batang Ai menunjukkan bilangan individu yang agak rendah. Oleh itu. himpunan ikan di hilir terjejas disebabkan oleh pengempangan loji kllasa hidroelektrik.

Kala kllnei: Kepelbagaiaan, Fallna lkan. Batang Ai, Hiliran, Kualiti Air

XII

1.0 Introduction

River system is essential for living as it provides a lot of functions such as

availability of food, transportation, generate hydroelectricity and water resource for

irrigation and drinking (Cooke et al., 2012).

Pieter Bleeker began his study on freshwater fishes in Borneo during period 1851­

1860 and this cause the interest of researcher on freshwater fishes (Mohsin and Ambak,

1983). Currently, more than one-third of primary freshwater fishes known are from Borneo

(Inger and Chin, 2002). Fishes in the ecosystem acts as a biological indicator for status of

the environment. Not only that, fish is an important resource on earth for human

consumption (Bayley and Li, 1996).

There are some studies that had been carried out in Sarawak to document the

diversity of fish fauna. Some of the studies done are by Nyanti et al. (1999) in Bario,

Kelabit Highlands, Jongkar (2013) at Padawan Limestone, Jeffrine et al. (2009) at Betong,

Nyanti et al. (2012) at Lutong River, Watson and Balon (1984) at Baram River, Parenti

and Lim (2005) at Rajang River Basin as well as Ahmad (2014) and Noor Azhar (2015) in

downstream of Batang Ai.

Batang Ai Hydroelectric Plant had been operating for closed to 30 years as it was

dammed in 1984 (Ling et al., 2012). The downstream of Batang Ai Hydroelectric Plant is

frequently subjected to fluctuation as release of water is needed in order to generate

electricity and this has affects the water quality of the river downstream. The presence of

hydrogen sulfide near downstream of Batang Ai HEP may cause the toxicity to affect the

composition of fish in the river (Ling et aI., 2013). According to Ahmad (2014), the high

level of pH and temperature fluctuations had been reported in the downstream of Batang

1

Ai HEP during the discharge of water from the reservoir. Although a few fish fauna studies

have been done downstream of the dam, the information on fish fauna further downstream

of Batang Ai HEP has not been reported.

Therefore, the objectives of this study to be conducted in the downstream of Batang

Ai HEP, near Engkilili, Sarawak were:

1. To document the fish diversity and fish composition in the downstream of Batang

Ai HEP,

2. To record the length weight relationship of six dominant species found in the

downstream of Batang Ai HEP,

3. To record the feeding habits and selected indices of six dominant species found in

the downstream of Batang Ai HEP, and

4. To determine selected water quality parameters in the downstream of Batang Ai

HEP.

2

2.0 Literature Review

2.1 Diversity and Distribution of Freshwater Fishes

According to Kotellat and Whitten (1996), around 3500 species of freshwater fishes

can be found in Asia. In the world, diversity of freshwater fish is the greatest in tropical

Southeast Asia water bodies (Wilkinson, 2013). A report done by Roberts (1989) stated

that phylogenetic relationship between freshwater fish in Borneo and freshwater fish in

Thailand, India and China shows related relationship. The distribution of fish was

relatively high in Malaysia as compared to other countries. Bishop (1973) reported that

freshwater habitats in Malaysia consist of over 300 species of freshwater fishes.

According to Khan et af. (1996), about three hundred and eighty species of fishes had been

documented in Malaysia. While a recent study carry out by World Wildlife Fund (2014)

shows that documentation of freshwater fish in Borneo had reached 394 species and 149 of

the species is found to be endemic to the area. While for Sarawak, it is reported that 254

species out of 449 species in Malaysia are found in Sarawak (Department of Fisheries

Malaysia (DoF), 2012).

According to research done by Noor Azhar (2015) in the downstream of Batang Ai

REP, 14 species from 7 families was recorded and the three most dominant species are

Cyclocheilichthys apogon, Hemibagrus planiceps and Hampala macrolepidota. Ahmad

(2014) reported that downstream of Batang Ai HEP was dominated by Cyclocheilichthys

apogon, Hampala macrolepidota, and Cyclocheilichthys armatus.

2.2 Dominant Species in Malaysia and Borneo

In Peninsular Malaysia and Borneo, the most dominant freshwater fish are

cyprinids which account for about 30 % of the fish composition and high percentage of

3

endemism is reported in Malaysia (Abdul Salam and Gopinath, 2006; Wilkinson, 2013).

According to Jongkar and Lim (2004) at Bau limestone, the abundance was highest for

family of Cyprinidae and then followed by Hemiramphidae, Balitoridae and Channidae.

Based on Wilkinson (2013), fish from the family cyprinids have different aspects in terms

of size and diet. Its diet is found to range from detritivores to piscivores.

The family of Cyprinidae shows high level of dominance of 86.2 % at upstream

and downstream of Batang Ai Hydroelectric Reservoir (Ahmad, 2014). According to

research done by N oor Azhar (2015), it shows that downstream of Batang Ai Hydroelectric

Dam was dominated by Cyprinidae (63%) which is 161 individuals of the total catch of

255 individuals.

2.3 River System

According to Mohsin and Ambak (1983), rivers can be classified into upper zone,

middle zone and lower zone. This classification of zone is caused by morphometry, degree

ofgradient and velocity of the river flow. Besides, there are many types of river ecosystem

that can be found. The range of freshwater rivers can be small and clean which does not

have the problem of pollution where it pass through rocky bottom and primary rainforest.

Upstream of rivers will eventually grows into bigger rivers downstream and with slower

river flow (Atack, 2006).

According to We1comme et al. (2010), the definition of rivers is described as open

and lots of headwater streams can be found in system of linear. River system will depend

on nutrient input by external environment. Classification of rivers can reach different level

oforders where it begins with first order stream and second order stream formed when two

first order stream merge. The level of orders continues as the river flows. River system

4

Pusat Khidmat Maklumat Akadf:\r-" UNIVERSI11l\1ALAYSIA SARAWAh

flows in such way that it is in unidirectional fonn and the current decreases as it flow from

headwater to downstream due to gradient differences present. Not only that, diversity of

.fish species and richness is found to increase as stream order increases (Wotton, 1991).

One of the factors that influence the fish species composition in river is the type of

bottom substrate of the river. For example, silty, muddy and sandy bottom attract more

benthic feeding species whereas in clay or rocky bottom substrate benthic feeding species

is hardly found. Besides, every habitat exist will have the dynamic equilibrium in

composition of species as the season and natural phenomenon are going to change the food

supply and living environment (Atack, 2006).

However, a study carried out by Abdul Salam and Gopinath (2006) reported that

river systems in Malaysia are listed as one of the most degraded ecosystems. As the rivers

are found to be degraded, it affects the population of fish the most.

2.4 Effects of Impoundment of Dam to Downstream Area

Impoundment of Dam at river tends to change and create a new ecosystem

especially to the downstream area as the natural flow regimes were affected (Baxter, 1997;

Alexandre et al., 2013). According to Quinn and K wak (2003), many species of fishes had

been recorded 30 years after impoundment at the White River in Arkansas which was

initially absent from the area. While Paragamian (2002) stated that after an impoundment,

insectivores are less likely to be tolerable to the changes of ecosystem as compared to

omnivores. According to Kinsolving and Bain (1996), the fish composition of river was

affected and population reduced due to impoundment of dam which causes fluctuations of

water level and the downstream of hydroelectric dams faces a longitudinal gradient of

change in community of fish in the river.

5

According to Supit and Ohgushi (2012) and Murchie et al. (2008), impoundment of

dam gives some impacts to the water quantity and water quality. In terms of water quantity,

when reservoir is created, the surface of water increases and cause higher level of

evaporation. Whereas from the perspective of water quality, the downstream of reservoir

tends to get more impact as it receives water from the reservoir. For example, higher level

of eutrophication would happen as consequences of limited exchange of water in the

reservoir and also aquaculture activities in the reservoir. Moreover, from a study by

Schouten (1998), water discharged from reservoir was unfavourable for aquatic organisms.

Vineet et al. (2012) reported the degradation of biodiversity in the downstream area

due to discharge of water from dam and it happens because of turbidity increases and

excess nutrients present. However, Ahmad (2014) stated that the presence of turbidity

value in the downstream of Batang Ai HEP is relatively low as the origin of water is from

lentic environment and suspended solids had settled down before discharge of water. From

a study done by Ahmad (2014), chlorophyll-a and water temperature of downstream

Batang Ai HEP were slightly higher. pH of river water in the downstream of Batang Ai

HEP was affected by the discharge of dam and cause pH values to be slightly acidic.

According to Friedl and Wiiest (2002), construction of reservoir affects the

biogeochemical cycles as flow of organic carbon, nutrient, oxygen and temperature were

interfered.

2.5 Feeding Habits

Feeding habits of fish can be determined by studying the stomach content and

varieties of food available in the river system (Arrignon, 1999). According to research

done by Blanco et at. (2003), the stomach contents that can be found in freshwater fish are

6

insects, fish, algae, copepod, detritus, zooplankton, sediment, macrophytes, cladocers,

rotifers and dipters.

In Malaysia, several studies that were related to documentation of feeding habits of

fish had been done. Some of these studies are by Khan et al. (1988) at Chenderoh

Reservoir, Perak, Peninsular Malaysia, Sarker et al. (2014) at Universiti Putra Malaysia,

Noor Azhar (2015) at downstream of Batang Ai Hydroelectric Dam, Lubok Antu and Goh

(2015) at Pelagus, Kapit, Sarawak. A study by Khan et al. (1988) at Chenderoh Reservoir

reported that Mystus nemurus is euryphagous as they feed on wide range of food available

at the bottom substrate of the reservoir. While Sarker et ai. (2014) documented that

Channa striatus is carnivorous. Moreover, Noor Azhar (2015) recorded that

Cyclocheilichthys apogon and Hemibagrus planiceps are omnivorous, meanwhile

Hemibagrus planiceps also shows carnivorous feeding habit. Goh (2015) reported that

Channa Lucius is carnivorous, Nemacheilus kapuasensis is insectivorous, Barbonymus

collingwoodii, Osteochilus waandersii, Rasbora caudimaculata and Rasbora lateristriata

are ommvorous.

2.6 Length-Weight Relationship and Condition Factor

Length-weight relationship is an important way to have a better management on

fisheries (Zakeyudin et ai., 2012; Sarkar et al., 2013). The length-weight relationship gives

us a guideline to measure how well the fish is growing and its health (Wootton, 1991).

This analysis can be applied by measuring the total length and weight of fish samples. The

fonnula used to measure length-weight relationship is W = aLb or log W = log a + b log L,

where W = weight (g), L = total length (cm) and a and b = constant. The growth pattern

can be determined by obtainjng the b value, where when b = 3.0, it has isometric or normal

7

I

growth rate. When b > 3.0, it is a positive allometric or over growth rate and when b < 3.0,

it is a negative allometric or poor growth rate (Schneider et at., 2000).

Condition factor is an ideal way to provide information on fish condition. The

equation is K= (100 W) / L3, where when K is small, the fish is consider light for their size

and when K is big, the fish is growing heavier for their size.

2.7 Water Quality

Malaysia government had provided two approved guidelines for the classification

of river water quality which is known as National Water Quality Standards (NWQS) and

Water Quality Index (WQI) (Zainudin, 2010). Vineet et at. (2012) stated that fish

composition is highly affected by water quality parameters. Examples of some of the water

quality parameters are temperature, depth, current and turbidity.

Temperature is one of the factors that affect the richness of fish in the rivers and

some fishes required specific optimum temperature in order to achieve better growth rate

(Yan et at., 2011; Ekubo and Abowei, 2011). According to Roth et at. (2010), way to

control the temperature of the stream is by using vegetation cover which serves as a shade

for stream to have lower temperature. Furthermore, dissolved oxygen level is another

critical factor that affects the fish population in the river system. Fish composition is

greatly affected by DO level as DO is interconnected with temperature of water and current

at which DO is inversely proportional to the temperature of water (Smale and Rabeni, 2011;

Ekubo and Abowei, 2011; Loures and Pompeu, 2012). According to Othman et at. (2002)

and Viessman and Hammer (2005), most of the fishes live in favourable environment of

DO with value of more than 5 mg/L and pH value between 6.5 to 9.0. Turbidity values of

water were affected by the amount of suspended solids present in the water bodies such as

8

clays, silts, debris, plankton, decomposers along with organic and inorganic compounds

(Gandaseca et al., 2011; Mustapha, 2008).

2.8 Gonadosomatic Index (GSI) and Hepatosomatic Index (HSI)

According to Adebiyi (2013), gonadosomatic index is a good indicator which

relates the relationship between size of gonad and size of fish. Gonadosomatic index is also

used to evaluate the percentage of body weight in fish that is used in eggs' production

(Adebiyi, 2013). Therefore, gonadosomatic index is an important aspect to have baseline

information on reproduction offish in the river.

According to Hismayasari et al. (2015), hepatosomatic index expressed the ratio of

liver weight and weight of fish. It is commonly used in fisheries to act as a marker for

status ofenergy reserves in the liver of fishes (Hismayasari et at., 2015).

2.9 Threats to River

As stated by Abdul Salam and Gopinath (2006), rivers in Malaysia are badly

degraded ecosystems and there are a lot of activities that cause this situation. Degraded

river systems are a bad situation that impact the fish assemblages and bring about lots of

negative impact to fisheries industry. Examples of activities that cause degradation of river

systems are encroachment of habitat, land clearing, reclamation of wetland and

construction of dam.

Besides, river systems in Malaysia are also affected by threat in term of biological.

According to Abdul Salam and Gopinath (2006), invasion of invasive species threaten the

population of native species in Malaysia waters. Some examples of the invasive fish

species in Malaysia are Osphronemus gourami, Cyprinus carpio, Ctenopharyngodon

9.

idellus, Trichogaster pectoralis, Oreochromis niloticus, Oreochromis mossambicus, Labeo

rohita and Barbodes gornionotus.

10